From 1f23816b8eb8fdc39990abe166c10a18c16f6b21 Mon Sep 17 00:00:00 2001 From: Changpeng Liu Date: Thu, 1 Nov 2018 15:40:35 -0700 Subject: virtio_blk: add discard and write zeroes support In commit 88c85538, "virtio-blk: add discard and write zeroes features to specification" (https://github.com/oasis-tcs/virtio-spec), the virtio block specification has been extended to add VIRTIO_BLK_T_DISCARD and VIRTIO_BLK_T_WRITE_ZEROES commands. This patch enables support for discard and write zeroes in the virtio-blk driver when the device advertises the corresponding features, VIRTIO_BLK_F_DISCARD and VIRTIO_BLK_F_WRITE_ZEROES. Signed-off-by: Changpeng Liu Signed-off-by: Daniel Verkamp Signed-off-by: Michael S. Tsirkin Reviewed-by: Stefan Hajnoczi --- drivers/block/virtio_blk.c | 83 ++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 81 insertions(+), 2 deletions(-) (limited to 'drivers/block') diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 086c6bb12baa..0f39efb4b3aa 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -18,6 +18,7 @@ #define PART_BITS 4 #define VQ_NAME_LEN 16 +#define MAX_DISCARD_SEGMENTS 256u static int major; static DEFINE_IDA(vd_index_ida); @@ -172,10 +173,48 @@ static int virtblk_add_req(struct virtqueue *vq, struct virtblk_req *vbr, return virtqueue_add_sgs(vq, sgs, num_out, num_in, vbr, GFP_ATOMIC); } +static int virtblk_setup_discard_write_zeroes(struct request *req, bool unmap) +{ + unsigned short segments = blk_rq_nr_discard_segments(req); + unsigned short n = 0; + struct virtio_blk_discard_write_zeroes *range; + struct bio *bio; + u32 flags = 0; + + if (unmap) + flags |= VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP; + + range = kmalloc_array(segments, sizeof(*range), GFP_ATOMIC); + if (!range) + return -ENOMEM; + + __rq_for_each_bio(bio, req) { + u64 sector = bio->bi_iter.bi_sector; + u32 num_sectors = bio->bi_iter.bi_size >> SECTOR_SHIFT; + + range[n].flags = cpu_to_le32(flags); + range[n].num_sectors = cpu_to_le32(num_sectors); + range[n].sector = cpu_to_le64(sector); + n++; + } + + req->special_vec.bv_page = virt_to_page(range); + req->special_vec.bv_offset = offset_in_page(range); + req->special_vec.bv_len = sizeof(*range) * segments; + req->rq_flags |= RQF_SPECIAL_PAYLOAD; + + return 0; +} + static inline void virtblk_request_done(struct request *req) { struct virtblk_req *vbr = blk_mq_rq_to_pdu(req); + if (req->rq_flags & RQF_SPECIAL_PAYLOAD) { + kfree(page_address(req->special_vec.bv_page) + + req->special_vec.bv_offset); + } + switch (req_op(req)) { case REQ_OP_SCSI_IN: case REQ_OP_SCSI_OUT: @@ -225,6 +264,7 @@ static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx, int qid = hctx->queue_num; int err; bool notify = false; + bool unmap = false; u32 type; BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems); @@ -237,6 +277,13 @@ static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx, case REQ_OP_FLUSH: type = VIRTIO_BLK_T_FLUSH; break; + case REQ_OP_DISCARD: + type = VIRTIO_BLK_T_DISCARD; + break; + case REQ_OP_WRITE_ZEROES: + type = VIRTIO_BLK_T_WRITE_ZEROES; + unmap = !(req->cmd_flags & REQ_NOUNMAP); + break; case REQ_OP_SCSI_IN: case REQ_OP_SCSI_OUT: type = VIRTIO_BLK_T_SCSI_CMD; @@ -256,6 +303,12 @@ static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx, blk_mq_start_request(req); + if (type == VIRTIO_BLK_T_DISCARD || type == VIRTIO_BLK_T_WRITE_ZEROES) { + err = virtblk_setup_discard_write_zeroes(req, unmap); + if (err) + return BLK_STS_RESOURCE; + } + num = blk_rq_map_sg(hctx->queue, req, vbr->sg); if (num) { if (rq_data_dir(req) == WRITE) @@ -802,6 +855,32 @@ static int virtblk_probe(struct virtio_device *vdev) if (!err && opt_io_size) blk_queue_io_opt(q, blk_size * opt_io_size); + if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD)) { + q->limits.discard_granularity = blk_size; + + virtio_cread(vdev, struct virtio_blk_config, + discard_sector_alignment, &v); + q->limits.discard_alignment = v ? v << SECTOR_SHIFT : 0; + + virtio_cread(vdev, struct virtio_blk_config, + max_discard_sectors, &v); + blk_queue_max_discard_sectors(q, v ? v : UINT_MAX); + + virtio_cread(vdev, struct virtio_blk_config, max_discard_seg, + &v); + blk_queue_max_discard_segments(q, + min_not_zero(v, + MAX_DISCARD_SEGMENTS)); + + blk_queue_flag_set(QUEUE_FLAG_DISCARD, q); + } + + if (virtio_has_feature(vdev, VIRTIO_BLK_F_WRITE_ZEROES)) { + virtio_cread(vdev, struct virtio_blk_config, + max_write_zeroes_sectors, &v); + blk_queue_max_write_zeroes_sectors(q, v ? v : UINT_MAX); + } + virtblk_update_capacity(vblk, false); virtio_device_ready(vdev); @@ -895,14 +974,14 @@ static unsigned int features_legacy[] = { VIRTIO_BLK_F_SCSI, #endif VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE, - VIRTIO_BLK_F_MQ, + VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES, } ; static unsigned int features[] = { VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY, VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE, - VIRTIO_BLK_F_MQ, + VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES, }; static struct virtio_driver virtio_blk = { -- cgit v1.2.3